Previous investigations suggest that a class of compounds called "amphiphiles" have immunosuppressive activity and may inhibit cytotoxic T cell (Tc-cell)-mediated lysis of certain targets by Tc-cells generated in the mixed lymphocyte reaction (MLR) and thus may find utility as immunosuppressive agents. Amphiphiles have a hydrophobic tail attached to a hydrophilic head group. The tail, generally of hydrocarbons, may consist of one or two chains, and the head group may bear a positive or negative charge, or may be uncharged. Because most biological membranes carry a net negative charge, the compounds used in the study by Ashman, et al [(1985) Mol Immunol 22:609 and (1986) Immunol Today 7:278] primarily involved cationic mono- and di-alkyl quaternary ammonium compounds. In particular, PCT publication WO85/05031 discloses a double-chained quaternary ammonium surfactant, didodecyl dimethyl ammonium bromide, when used at dosages between 10 ng/ml and 100 ug/ml, was immunosuppressive on alloreactive Tc cells.
A study of the alleged immunosuppressive activity reported in the above literature was initiated, given the use of these compounds in commercial formulations of hair care products, nonirritant shampoos, liquid soaps and gels, disinfectants, laundry additives and, together with heterocyclic quaternaries, as particularly effective fabric softeners (Linfield (1970) In: Cationic Surfactants (ed. Jungermann, E.) pp. 48-52, Marcel Dekker, Inc., New York). The results of this study are summarized in Coy, et al. (1987) Federation Proceedings 46(3):540, Abstract No. 1303. This publication provides the concentration ranges in which five amphiphilic compounds exhibited immunosuppressive and/or cytotoxic activity in the one-way mixed leukocyte reaction (MLR). The authors conclude that there may be a critical concentration range in which immunosuppression is achieved without cytotoxicity. Exposure of the promyclocytic cell line HL-60 to these amphiphiles caused dose-dependent inhibition of proliferation but it also significantly reduced cell viability. However, at concentrations that did not alter viability, no inhibition of proliferation was seen. Neither betaines or sulfobetaines were included in this study.
A more exhaustive study with 29 amphiphiles was prepared and reported at the Biomedical Research Committee of the Soap and Detergent Association, held Jul. 21, 1988 in New York, N.Y. In the MLR, seventeen of twenty-nine compounds investigated produced greater than 70% inhibition without toxicity and six compounds were toxic (i.e., end viability and live cell percentage were less than 50% of the control). In order to determine whether the inhibitory capabilities of the amphiphiles were specific for lymphocyte proliferation or whether the amphiphiles would inhibit proliferation of other cells, fourteen compounds, including two betaines, were tested on a battery of cell lines. The only betaines tested were N-(carboxymethyl)-N,N-dimethyl-1-dodecanaminium hydroxide (HB-1) and N-dodecyl-N,N-dimethyl-1-ammonio-1-propanesulfonate (HSB-3).
The results showed that the effect of these compounds was antiproliferative (lack of cell growth, but viable cells) rather than immunosuppressive (cellular failure to respond to extracellular chemical stimulus). At the concentrations tested HB-1 was found to be inhibitory and toxic and HSB-3 was found to be noninhibitory and nontoxic.
Ernst and Arditti, (1980) Toxicology 15:233-242 tested thirteen nonionic surfactants for toxic effects to HeLa cells. The surfactants consisted of fatty alcohol ethoxylates and 6 amphoterics (all 3-(alkyldimethylammonio)-1-propanesulfonates having an alkyl chain from 8 to 18 carbon atoms. Lethal concentrations ranged from 16 to 320 mM. Ernst et al., did not test these compounds for their ability to inhibit growth of HeLa cells.
Farber and Ichinose, (1958) Cancer Res 18:1209 report that betaine was relatively effective in preventing chronic morphological changes in the liver, including cancer formation, induced in rats fed ethionine. Possible mechanisms for its effectiveness were presented, including its possible role as a substitute for methyl transferase in the conversion of homocysteine to methionine. It is known that methionine is capable of inhibiting many effects of ethionine administration.
A principal object of this invention is to provide quaternary ammonium compounds which are biologically active antineoplastic agents.